Gregory's Server@gamingonlinux Open Surge is a very interesting project, I remember when I tried some builds many years ago (maybe it was 2013 or 2014)
Alemart, the developer, had previously made a Sonic fangame called Open Sonic, unlike other fangames made with MMF2 and similar softwares, he made an open source engine for this fangame.
It was later abandoned in favor of its new game Open Surge, with the new Surge Engine and SurgeScript object-oriented scripting language